Gas prices on the rise, top $4

Gasoline prices are once again on the move, climbing past $4 a gallon with the long Memorial Day weekend just down the road – and with it, the traditional start of the summer travel season.

Industry experts said maintenance at a key refinery and low statewide supplies of gasoline appear to be driving up pump prices. They said they expect prices to level off in the coming days and then drop in June, after the rush of the long holiday weekend.

In Orange County, the price of an average gallon of regular unleaded jumped by nearly 17 cents in the past week, according to AAA's daily Fuel Gauge report. It crossed the $4 line on Saturday and stood at about $4.06 on Monday.

The conditions that helped create this latest price spike were beginning to take shape in late April, when the California Energy Commission reported that statewide fuel inventories were far below normal. In California's volatile gasoline market, even the threat of a supply problem is enough to point prices straight up, analysts said.

Those inventories were beginning to recover by last week. Then ExxonMobil announced it was shutting down several processing units at its Torrance refinery for what it described as "scheduled maintenance."

That shutdown will impact production for several weeks, the company said in a statement, although it was quick to add that it expects to be able to meet its contractual obligations. Nonetheless, that kind of announcement "tends to cause a little anxiety" in the market, said AAA spokesman Jeffrey Spring.

ExxonMobil's announcement is "panicking the market, creating the perception of scarcity," said Charles Langley, an analyst with the Utility Consumers' Action Network in San Diego. "They're planning their maintenance at a time of year when gas prices usually go up and demand is usually high," he said.

Several other California refineries underwent maintenance slowdowns earlier this year, which also spiked pump prices. Those earlier slowdowns may have been behind the lower gasoline inventories in late April, said Patrick DeHaan, an analyst with the website GasBuddy.com.

Those refineries should be getting back to normal production, and inventories are back to where they should be for this time of year, DeHaan said. Typically, he said, gas prices ease after the long Memorial Day weekend.

Then again: "We know prices always come down slower than they go up," he said.